Temporary power supplier Aggreko delivered a welcome ray of light among the gloomy economic forecasts yesterday.

In a bullish interim management statement the company confirmed it was now predicting 50 per cent growth in pre-tax profits by the year end.

That would put it on course to deliver more than £180million - well ahead of analyst expectations.

Royal Bank of Scotland analysts immediately upgraded predictions for the full year to £188m.

They said: "Aggreko confounded sceptics with a very strong IMS statement, prompting further upgrades to forecasts and containing no signals of a slowdown in key markets.

"To us, that confirms the quality and resilience of the business models in each of the four divisions."

The company also said it will be building a £20 million manufacturing facility near Dumbarton after fears it would locate operations in China.

Rupert Soames, chief executive of Aggreko, said: "We are all absolutely delighted we were able to make the sums add up for this major investment, in part due to assistance from the Scottish Government.

"Over recent years we have built up world-leading design, engineering and manufacturing skills in Dumbarton, and employ over 250 people there.

"By building our new facility in the same area, we will keep this team together, and, hopefully, will be able to expand it."

Glasgow-based Aggreko said growth in the third quarter had been stronger than expected with total revenues up 39 per cent.

Revenues in the Middle East, Asia Pacific and Central and South America increased by 59 per cent, helped by a Û22m boost from a contract with the Beijing Olympics.

Sales in North America were up 10 per cent as customers needed support following Hurricanes Gustav and Ike, though European revenue fell three per cent on the same quarter last year. Aggreko said: "In North America, storm-related revenues have been strong and underlying demand is currently holding up better than we expected. In Europe, we expect revenues in the second half to be similar to last year in constant currency.

"We now anticipate constant currency profits in Europe will be similar to the second half last year, and North America's profits will be well ahead.

"Momentum remains very strong in Aggreko International, with our businesses all expected to make further progress throughout the remainder of the second half, helped in part by a very rapid redeployment of the fleet used to support the Beijing Olympics.

"We now anticipate Aggreko's performance will exceed market expectations with profit before tax likely to be 50 per cent higher than last year."

Net debt increased by £32m since June to £310m. In the third quarter Aggreko secured additional funding of £60m from its banks to bring total facilities to£463m.

The company also announced structural changes with a new merged Middle East and European division.